I can't help on the chimney, I've used masonry chimneys for my perminent installs.

For the coal bin, just about any shape you can build that has 120-130 cubic feet inside will hold 3 tons of coal. Coal is about 40-42 cu ft per ton. If you are going to have coal delivered, you need to make it accessable to the delivery truck's chute. If you are going to bring the coal in yourself, then whereever you can put it where you can get to it to both fill it, and remove the coal to feed your stove.

A box made from 4x8 plywood for sides and 4'x4' ends is 4'x4'x8'=128 cuft divided by 40=3.2 tons.

Use 2x4's to make a framework to back up the plywood, the coal will flow like ball bearings or pea-gravel and exert a lot of force on the sides of the box, trying to get out of the box.

Take a look in the 'coalbin photos' thread, lots of ideas there.

Welcome to the forum, it's a bit slow right now, but will pick up with cold weather.